Who best exemplifies the basic essence of human nature: greedyexecutives engaged in corporate fraud; Mike Tyson, the aggressive boxer; or thecourageous, compassionate Americans who risked their lives to save strangers onSept. 11?

If you chose only the personifications of greed andaggression, you are neglecting a vital part of our nature, according to ShelleyE. Taylor, UCLA psychologyprofessor. In a new book, Taylor argues that nurturing others and caring fortheir needs are as wired into our genes as our aggressive and competitivenature.

"The tending instinct is every bitas tenacious as our more aggressive, selfish side," Taylor argues in "TheTending Instinct: How Nurturing Is Essential to Who We Are and How We Live"(Henry Holt). "Tending to others is as natural, as biologically based, assearching for food or sleeping."

Aninternationally renowned scientist in thefield of stress and health, Taylor conducted 25 years of research and analyzed more than 1,000 research studies beforewriting this book.

"I originally assumed that biologylargely determines behavior," Taylor said, "and so it was a tantalizingsurprise to see how clearly social relationships forge our underlying biology,even at the level of gene expression. Chief among these social forces are theways in which people take care of one another and tend to one another's needs.An early warm and nurturant relationship, such as mothers often enjoy withtheir children, is as vital to development as calcium is to bones.

"The benefits that tendingprovides to children, especially those with genetic risks, are substantial.Children who are well tended in early childhood grow up with better social andemotional ways of meeting the world. Even in adult relationships, we tend toeach other's needs in ways that sustain long and healthy lives."

Life,business and relations between the sexes are often depicted as battlefields —"dog eat dog" — where the successful outmaneuver and overpower the weak.Taylor, whose research is federally funded by the National Science Foundationand the National Institute of Mental Health, finds this metaphor to be ahalf-truth, at best.

"Tending isinstinctive, and affects our biology at every stage of life," she said. "Wehave neuro-circuitrys for tending as surely as we have biological circuitry forobtaining food and reproducing ourselves. How people fare in times of stress —from how calm they are to their likelihood of becoming ill — depends on thequality of the tending they receive."

What roledoes our genetic makeup play in determining our behavior?

"The genomeis like an architect's first plan, a rough projection of how a person may turnout," Taylor argues. "This plan is revised during the course of the buildingprocess. The kitchen is rotated 90 degrees, the living room is extended a fewfeet. Later, the owner adds a bathroom, perhaps even a second story. This iswhat happens when genes meet the environment in which they find expression, andtending is a large part of this environment.

"From lifein the womb to the surprisingly resilient brain of old age, the socialenvironment molds and shapes the expression of our genetic heritage until thegenetic contribution is sometimes barely evident. A mother's tending cancompletely eliminate the potential effects of a gene; a risk for a disease canfail to materialize with nurturing, and a genetic propensity may lead to oneoutcome for one person and the opposite for another, based on the tending theyreceived.

"Who we are— our character, even our physical health — depends on the people who tend tous and how well we get along with them — our mothers, fathers, friends andlovers."

Earlytending has an extraordinary impact on children, Taylor documents. Showing anexample of the devastating effects on children who received little love ortending, Taylor cites the hundreds of thousands of Romanian orphans housedtogether in desperate conditions at the end of the Ceausescu regime in 1990.With few workers to care for large numbers of children, relief workers were shockedto find "room after room of children who rocked back and forth, hit their headsagainst the walls, and grimaced oddly, giving no sign they had registered thatanyone new was present," she writes. "Others simply stared at the strangerswith big, sad eyes.

"Theiremotions were stunted. They took little joy in their surroundings, and were notbothered by reprimands or criticisms. They just didn't care. They weren'ttortured or raped. They just weren't loved, held, hugged or taught to feelemotions or how to recognize them in others.

"The firstfew years of life are critical for building these emotional responses to life.If a child fails to get warm, responsive contact with another person duringthose years, the disadvantages may never be fully overcome."

As theSoviet bloc crumbled, Eastern Europe's newly free countries experienced anabrupt decline in the marriage rate, a staggering increase in divorce, a steepdecline in the birth rate, dramatic increases in heart disease and fatalaccidents, and a plummeting life expectancy. People who were expected to liveinto their 70s were dying in their 40s and 50s instead. The threat to lifeexpectancy hit young and middle-aged men especially hard, particularly thosewho were single. In 1994 a Russian man's life expectancy had decreased to just57 (from 64 five years earlier). Men in the former East Germany suffered a 40percent increase in their death rate.

"Women fared better than men because they had informalties in place that helped them negotiate the new social and economic order,"Taylor writes. "Using well-honed networking skills, they were able to acquirefood and other goods to maintain their now reduced standard of living. Womenand children died, too, but in far fewer numbers, sustained through the transitionby the social bonds they had created and nurtured. When a society's tendingsystem breaks down, illness and death can follow, sometimes in astonishinglyshort order. Men, in particular, are vulnerable."

Among older workers in the United States, those withlittle social support die earlier, Taylor said. How well workers are treated bytheir immediate supervisor makes a large difference in their physical andmental health, especially for men, Taylor writes. This "tending," or lack ofit, by your supervisor, affects your risk for coronary heart disease or a heartattack, as well as depression and anxiety.

Nurturingcontact with parents in early childhood, combined with social support duringtimes of stress, good friends (especially female friends), and a strong, lovingrelationship (especially with a wife) "all protect against the psychologicaland health problems that stress otherwise promotes," she writes.

People withsocial support have "younger" stress systems and better protection againstmajor chronic diseases, Taylor writes. Strong ties with family and closefriends protect against health ailments, while social isolation increases therisk for all causes of death, including heart disease, cancer, strokes andaccidents.

"More than100 scientific studies show that people who have social support and who areconnected to their families, their colleagues at work, their communities, theirchurches and their friends all prosper biologically," Taylor said.

Women oftenget much of their social support from other women, and women's friendships arevital to their mental health, she writes. Throughout life, women seek moreclose friends than men do, and create larger social networks for themselves.

Women'snetworks become especially important in stressful times, meeting a variety ofneeds, including raising children, protecting against violence and coping withstress.

Even amonganimals, she writes, females enjoy the comfort of one another's company. In astudy of Norway rats, for example, females housed together in groups of fivelived 40 percent longer than rats that were housed alone. Among prairie voles(a small rodent), males react to stressful conditions by seeking contact withtheir female mates, while females turn not to their mates, but to other female"friends." Female bonobos (monkeys) form intense, long-lasting bonds with otherfemales, much more so than males.

From vervetmonkeys to humans, mothers often treat their young the way they were treated inchildhood. In monkeys, mothers who were mistreated or deprived in infancy donot mother their own offspring as well as nurtured monkeys do, Taylor writes.Men and women who were abused as children are likely to become abusive parentsthemselves, she writes, and children who do not receive much physical attentionor warmth are at risk for a wide range of serious physical and mental healthproblems.

Taylor's ownresearch over many years shows that turning to one's social group for safetyand support is a common way for people to cope with stress. "The fact that onecan see a similar pattern in animals suggests that turning to others may havequite old biological origins," she writes.

Acrosscultures, girls typically receive training in tending from an early age, Taylorwrites, beginning with playing with dolls and caring for younger siblings,baby-sitting for others' children, and later caring for their own children, asick husband and elderly parents.

With theenormous popularity of cell phones, Taylor noted, we now carry our socialsupport network with us wherever we go. Friendships are vital, she said, and"social ties are the cheapest medicine we have."